The present invention relates to medical devices in general and catheter assemblies having flexible radiopaque markers in particular.
Catheters have found widespread clinical use, for both diagnostic and interventional procedures. In performing, for example, intravascular catheter procedures, a physician typically uses a fluoroscope (e.g., an X-ray machine) to visualize a patient""s vascular structure. To assist the physician in guiding and positioning the catheter within the patient""s vascular system, catheters typically have one or more marker bands affixed to the shaft that are highly visible under the fluoroscope.
FIGS. 1A and 1B illustrate an example of a balloon catheter assembly and a marker band, respectively, from the prior art. The catheter assembly 10 comprises a shaft 15 and a balloon member 14 disposed around a distal section of the shaft 15. The balloon member 14 has a proximal portion 11 and a distal portion 13 and an inflatable portion 12 therebetween. The proximal portion 11 and the distal portion 13 of the balloon member are affixed to the shaft 15. The catheter assembly 10 depicted in FIG. 1A has a single marker band 19 positioned to indicate a midpoint of the inflatable portion 12 of the balloon member 14.
The marker band 19 is shown in an expanded view in FIG. 1B. The marker band 19 is a solid band of a radiopaque metal, such as gold, platinum, tungsten, iridium, etc. and alloys thereof. Typically, the marker band 19 is slipped around and onto the shaft 15 and then affixed to the shaft with an adhesive or by heating the shaft.
Vascular structures can be very tortuous, and marker bands of the prior art present an impediment to navigating the catheter through such tortuous anatomy, especially around a tight bend, because such marker bands are rigid and have no flexibility. The marker band""s rigidity additionally present problems to passing the catheter through a lesion.
The present invention provides catheter assemblies having at least one flexible radiopaque marker affixed with the shaft. In one embodiment of the present invention, the flexible radiopaque marker is a segmented band of a radiopaque material. The segmented band further has a longitudinal slit running from one end of the segmented band to the opposite end of the segmented band. In another embodiment, the flexible radiopaque marker comprises a coil of a radiopaque material. The radiopaque material may comprise a radiopaque metal. Alternatively, the radiopaque material may comprise a polymeric material loaded with a radiopaque agent.